With QueenDeath's failed attempted at another invasion of Atlantis, she is mustering her forces to destroy the city, once and for all. She sends a single hive with an escort cruiser to scout and get a sense of the defense that will be mounted.

With Atlantis's ZPMs drained, the expedition launch both their 304s, hoping they will be sufficient to combat the enemy. (SGA: "Legacy: Allegiance")

The hive and it's escort jump out of hyperspace, and start scanning for Atlantis. They close on the planet to get a better look, but they are intercepted by the two battlecruisers. At this point the Tau'ri learn that the hive is using an energy shield, something they have never previously encountered on a Wraith ship. A long fight ensues, with the Hammond keeping the hive busy while the Daedalus takes out the cruiser. Although the cruiser is disabled the Daedalus takes damage to their engines, redering them unmovable. The Hammond continues to fight, keeping the inert cruiser between it and the hive. Colonel Carter prepares to crash the ship into the hive in a last desperate measure, after beaming off her crew, but then the beams go offline and she prepares for the kamikaze run. As Carter performs her suicide run, the Daedalus rejoins the fight, distracting the hive ship. Seeing her chance as the hive ship turns its damaged stern towards the Hammond, Carter diverts all power to the rail guns and fired. The rail guns were able to fire five shots before the Hammond lost all power. The shots impacted the hive ship's damaged stern, destroying the ship. While Carter would've died on the powerless Hammond, the Daedalus was able to save her by beaming her aboard. (SGA: "Legacy: Allegiance")

This is one of the first times that human ships have been able to take down a hive without nuclear warheads, Ancient weapons or such.

Carter's attempt to perform a suicide run with the George Hammond is similar to what she did in an alternate timeline with the Phoenix, the Hammond's counterpart in that timeline. Unlike there, she and her ship survived the battle.